When I did mine I ran into the same problem, I only had a ftlb bar. If I rememer there is a pretty wide range in tolerance on torque specs for those. My goal was to get in that window and to make sure all the bolts where evenly torqued(Thats the most important thing imo). To find inch lbs in foot lbs simply take your inch number and divide by12. Ex 25inch lbs equals 2.08 feet lbs. To find feet lbs in inch lbs take you feet number and multiply by 12.Ex15ftlbs equals 180inch lbs. So if you are looking for 15 inch lbs that equals 1.25 feet lbs. Take you ftlb bar and adjust it down to aprox 1.25 ftlbs. You will find that your will run out of marks as you adjust down that far on your torque bar. You will have to figure out your adjustment per revolution of the handle. (Just an Ex) but when you take it down to its last mark say 10 lbs you need to know that one rev will subtract another 1lb, in this case you would make a total of 8.75 revolutons to achieve you 1.25 mark. That was just an example, you bar will be different. Does that make sense? I hope I helped haha.