If you're not in a hurry and have an option IN Singapore, as opposed to ordering something online, then I'd at least have a look. PhysicsonIce has sage advice.
I know nothing of SPTeri's, but can comment on Riedells- they are relatively narrow and straight, so the last expects a forefoot about the same relative width as the heel. If you look at Kinzies closet, there are some size charts on there for most of the brands, and instructions on how to have someone measure your feet (too difficult to do yourself- the width changes as you sit down and stand up...). This should give you an idea, I would still send tracings or get measured by a professional.
I have talked directly with reps at Jackson and Riedell. They are very responsive to the phone and email and willing to answer questions. I'd encourage you to talk to them directly. I'm in the same situation as you (so is PhysicsonIce, actually) where there are no or very very few skate shops, and near to no knowledgeable staff in them. It makes the process of buying skates, which is already stressful, even more so.
If you already wear Jacksons and are happy with the fit, look at their Finesse (very soft boot) and Elite Dance (much stiffer) models. We have a couple of dancers in our club in the Finesse. If you're a big knee bender and very hard on your skates you might find them too soft though. I tried on Jacksons and Edea dance boots last time I got skates. I have funny feet, very narrow heels relative to my forefeet, so neither worked for me, both in C width were very comfortable in the front, but too wide in the heel, the Edeas much moreso than the Jacksons.
But it sounds like you might be able to try some things on, so do that!!!! Make sure your heel doesn't slip and that you have room in the balls of your feet (remember your feet will swell after skating for a while, so what feels all right in the store may not feel so all right after an hour on the ice....).
For blades, anything goes, really. If you're in the aspire why not consider the Ultima Dance blade, or their Finesse (entry level dance/synchro). My skate fitter in the US really likes the Ultima line- their quality control, he says, is top notch so there's very little risk of getting warped or otherwise misshapen blades (this can happen from MK/Wilson). He's been in business a long time and is very well respected in the US skating community. So I trust him. Another reason to stick with the Ultima line is the 8'rocker. The only other dance blade with the 8' is one of the Wilson Dance models (Superdance?
Check me on that!!!!!). The others, Coronation Dance (Wilson) is a very good entry level dance blade, and MK Dance which is what the elite dancers use. I'm on Vision Synchros, and they're just fine for dance. But all of these have a 7' rocker, which will take some adjustment. Not impossible for sure, but more than with the Ultimas.
Fwiw, I'm in dance boots now. I love the low back and the toe point I can get out of them, but I wish they were higher on the sides. I just don't feel comfortable in them, even after 2 seasons. I'm pre-silver too, but I did a lot more freestyle growing up. Just something to think about when you're trying them on.