Be careful with regular slin as well. It can catch a lot of people out. I have experimented with slin quite a lot regarding carb timing and amounts. When using humulin-r or novolin-r I would have to be extra careful when timing my post workout meal (after having intra aminos and carbs). Regular slin made me go badly hypo a few times when I experimented with timing (especially about 3-4 hours post workout).
I find very short acting and long acting are in many ways easier to control. Long is very forgiving and you just eat your normal meals. Short you have to be planned and eat well beforehand and for me I would generally sip on aminos and carbs most of it's active life. Then I would have a post workout meal. As it's only active for a few hours it was very easy to control.
Now because regular is active for longer but still spikes relatively fast I found I had to be extra careful especially after my post workout meal (if I took it pre). I could have loads of carbs intra and then again post but if I left my 2nd post workout meal for longer it could catch me out. Carb timing is just as important as carb quantity. I could have 10iu and have even 200g carbs (so loads) in the first 3 hours then I would get hit later on.
With 10iu regular you should be fine just make sure you sip your intra throughout training then after have a decent amount (approx 60-80g) of carbs post workout and then some more (maybe 40g) approx 1.5 hour later just to be safe. Obviously I don't know your exact goals so amounts could vary but when training you would to have more than enough aminos and carbs when it's active to ensure maximum fullness and recovery. Pick amounts so you get the most out of the slin instead of just looking at it as the lowest amount not to go hypo. I would also recommend adding in other supps when using slin. The main 2 supps being EAA's (approx 20g) and 5-10g glutamine as they will minimize the chances of going hypo and also aid in recovery etc. Other useful supps would be things like creatine, glycerol, citrulline malate etc.
I plan to start slin myself soon. I need to order new slin but have 2 1/2 lantus pens, 1/2 humalog pen, 1/2 humalog vial and last night I found 1/2 humulin-r vial I had forgotten about. It expired in 2018 but it will still be gtg

My plan is to go with lantus then swop over to something else. My fav slins are rapid, fast then slow in that order. So I always got the best results using log or regular.