HP and Dropzone both have VERY valid points,,,, that is the logic I use when purchasing a trailer as well.
I try make my towing purchases with two ideals.... I get way more trailer than I know I need (both size and build quality),,, and I pull with way more truck than I know I need. Not everyone has the budget for this mentality,,, but if you do, I find it to be worthwhile.
Tandem axle if I'm hauling anything heavy or of any value,,, and always get wider/longer than I think I need. If a 12' will do,,, I get the 14',,, if a 6.5' wide trailer will do,, I get the next size up, etc. Nominal extra money,,,, but it makes my travels less stressful and more enjoyable. Also,,, you will always have extra "gear" you forgot to think about when doing all your dimensional calcs for the SXS.
I also purchased one with 24" side rails with expanded metal. VERY useful for other chores around the house, AND they are bolted on, so they come off fairly easily if you don't want them on for any reason. Peace of mind for me as well in case a tiedown lets go or the like.
Everyone has a budget for sure,,, but a trailer is NOT the place to skimp when you are putting your VERY expensive toy on it and driving around with a million other lunatics all paying more attention to their phones than the road. Just save up for another few months.
Something to think about.