Polymer capacitors are readily available for voltages of 100 and under although modern low ESR electrolytics make perfectly fine replacements for tantalums and are, of course, available in a wider range of voltages..? As for the radial leaded packages very small diameter PTFE tubing is readily available for only a few dollars - dress the leads with it or just put down the appropriate sized pieces of Kapton tape over any traces that may be a shorting hazard.? It will not as rigid of a attachment as a axial package but unless the item will be in a fairly high vibration environment that doesn't matter - and if so, use a dab of the appropriate adhesive.
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Hal
Harold Foster